This invention relates to a method for manufacturing polyesters, in particular, to using a titanyl oxalate, such as lithium titanyl oxalate, as the catalyst for such reaction in combination with a catalyst enhancer such as a metallic oxalate like lithium oxalate to provide fast reactions with improved properties such as reduced acetaldehyde content and good color properties for the resulting polyester at substantially reduced catalyst levels. A synergistic relationship has been discovered between titanyl oxalate catalyst and the catalyst enhancer. A synergistic relationship has also been discovered between the titanyl oxalate catalyst, catalyst enhancer and a metallic cocatalyst such as antimony oxide or antimony triacetate.